Throttle device

ABSTRACT

Provided is a throttle device including a total of two throttle units in each two cylinders in an engine  1 , each of the throttle units having a unit body having intake air passages corresponding to four cylinders of the engine, a throttle shaft rotatably supported by the unit body, throttle valves secured to the throttle shaft to open and close the intake air passages for the cylinders, a motor, and a deceleration mechanism decelerating rotation of a drive shaft of the motor and transmitting the decelerated rotation to the throttle shaft, in which a deceleration ratio of the deceleration mechanism provided in a first throttle unit and a deceleration ratio of the deceleration mechanism provided in a second throttle unit out of the two throttle units are different from each other.

CROSS-REFERENCE TO RELATED APPLICATIONS

This Application claims priority from Japanese Patent Application No.2019-219688 filed on Dec. 4, 2019, Japanese Patent Application No.2019-219689 filed on Dec. 4, 2019, and Japanese Patent Application No.2019-219690 filed on Dec. 4, 2019, which are incorporated herein byreference in their entirety.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to a throttle device controlling intakeair of an engine.

Description of the Related Art

Many of engines mounted on vehicles such as motorcycles for driving thevehicles to travel have a plurality of cylinders to obtain high outputs.Further, multi-throttle devices that provide throttle valves for each ofthe plurality of cylinders have widely been employed in motorcycles toimprove engine outputs.

For example, Japanese Patent Laid-Open No. 2005-282463 discloses aninline four-cylinder engine provided with a throttle valve in each ofintake air passages of cylinders. The engine disclosed in theaforementioned document includes a motor to drive a throttle valve for afirst cylinder and a throttle valve for a second cylinder, a motor todrive a throttle valve for a third cylinder, and a motor to drive athrottle valve for a fourth cylinder. This enables degrees of opening ofthe first cylinder, the second cylinder, the third cylinder, and thefourth cylinder to be individually controlled by controlling driving ofeach motor. Further, the engine disclosed in the aforementioned documentincludes a cylinder deactivated operation function of deactivatingoperations of a part (the third cylinder and the fourth cylinder) of theplurality of cylinders.

According to such an engine provided with throttle valves for each ofcylinders and provided with a plurality of motors for driving thethrottle valves as described above, cases in which degrees of opening ofthe throttle valves significantly differ from each other may occur dueto the individual control of the driving of the motors. According tosuch an engine provided with the cylinder deactivated operation functionas in the aforementioned document, throttle valves of the part ofcylinders that are deactivated are set to have predetermined degrees ofopening (in a closed state, for example) at the time of the cylinderdeactivated operation, and the degree of opening of the throttle valvesof the cylinders that are deactivated and of the cylinders that are notdeactivated at the time of the cylinder deactivated operation may thussignificantly differ from each other, for example.

There is a possibility that when it is attempted to control all thethrottle valves to have the same target degree of opening, for example,from such a state in which the degrees of opening of the throttle valvessignificantly differ from each other in this manner, the difference indegree of opening of the throttle valves is not immediately solved atthe time of shifting to the target degree of opening and a driver of thevehicle have an uncomfortable feeling due to a difference in outputs ofthe cylinders caused by the difference in degree of opening of thethrottle valves.

SUMMARY OF THE INVENTION

An object of the present invention, which has made in view of suchcircumstances, is to provide a multi-throttle valve device that isemployed in multi-cylinder engine and is capable of curbing anuncomfortable feeling due to a difference in outputs of the cylinders.

In order to achieve the aforementioned object, there is provided athrottle device according to the present invention including: aplurality of throttle units provided in an engine for each of cylindersor for each of cylinder groups, each of the throttle units including athrottle body having intake air passages corresponding to the pluralityof cylinders of the engine, a throttle shaft rotatably supported by thethrottle body, throttle valves secured to the throttle shaft to open andclose the intake air passages for the cylinders, a motor, and adecelerator decelerating rotation of a drive shaft of the motor andtransmitting the decelerated rotation to the throttle shaft, in which adeceleration ratio of the decelerator provided in the first throttleunit and a deceleration ratio of the decelerator provided in the secondthrottle unit out of the plurality of throttle units are different fromeach other.

According to the throttle device of the present invention, it ispossible to set the opening/closing speeds of the throttle valve of thefirst throttle unit and of the throttle valve of the second throttleunit to be different from each other and thereby to immediately solve adifference in degree of opening of the throttle valves in a case inwhich the first motor and the second motor are driven to have the samepredetermined degree of opening from a state in which the degrees ofopening of the throttle valves are different from each other. It is thuspossible to quickly solve a difference between an output of thecylinder, intake air of which is controlled by the first throttle unit,and an output of the cylinder, intake air of which is controlled by thesecond throttle unit, to obtain a smooth engine output, and to curb anuncomfortable feeling of a driver.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from thedetailed description given hereinafter and the accompanying drawingswhich are given by way of illustration only, and thus, are notlimitative of the present invention, and wherein:

FIG. 1 is an external view of a throttle device according to anembodiment of the present invention;

FIG. 2 is an overview configuration diagram of a throttle unit;

FIG. 3 is an internal structure diagram of a deceleration mechanism in afirst throttle unit;

FIG. 4 is an internal structure diagram of a deceleration mechanism in asecond throttle unit;

FIG. 5 is an electric circuit diagram for driving the throttle device;

FIG. 6 is a graph illustrating a transition example of a degree ofthrottle opening at the time of shifting from a cylinder deactivatedoperation to an ordinary operation;

FIG. 7 is an assembly diagram of an attachment portion of a returnspring in the second throttle unit;

FIG. 8 is an explanatory diagram illustrating an installation state ofthe return spring in a first throttle unit; and

FIG. 9 is an explanatory diagram illustrating an installation state ofthe return spring in a second throttle unit.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, an embodiment of the present invention will be described onthe basis of drawings.

FIG. 1 is an exterior view of a throttle device 10 according to anembodiment of the present invention. FIG. 2 is an overview configurationdiagram of a throttle unit (second throttle unit 12). FIG. 3 is aninternal structure diagram of a deceleration mechanism 20 (decelerator)in a first throttle unit 11. FIG. 4 is an internal structure diagram ofa deceleration mechanism 45 (decelerator) in the second throttle unit12.

The throttle device 10 according to the present invention is amulti-throttle device attached to a multi-cylinder engine. The throttledevice 10 according to this embodiment is employed in an inlinefour-cylinder engine 1 mounted on a vehicle such as a motorcycle. Forthe engine 1, four cylinders (2 a, 2 b, 2 c, and 2 d) from #1 to #4 aredisposed to be aligned in a vehicle width direction (left-rightdirection) in the vehicle.

As illustrated in FIG. 1, the throttle device 10 has a first throttleunit 11 (throttle unit) for a #1 cylinder 2 a and a #2 cylinder 2 bdisposed on one side of the engine 1 in the vehicle width direction anda second throttle unit 12 (throttle unit) for a #3 cylinder 2 c and a #4cylinder 2 d disposed on the other side of the engine 1 in the vehiclewidth direction. The first throttle unit 11 and the second throttle unit12 are disposed to be aligned on the left and right sides in the vehiclewidth direction.

The first throttle unit 11 and the second throttle unit 12 areconfigured to be symmetric on the left and right sides except fordeceleration mechanisms 20 and 45, which will be described later.

The first throttle unit 11 includes a first segment body 14 a in whichan intake air passage 13 a of the #1 cylinder 2 a is formed and a secondsegment body 14 b in which an intake air passage 13 b of the #2 cylinder2 b is formed.

The second throttle unit 12 includes a second segment body 14 b in whichan intake air passage 13 c of the #3 cylinder 2 c is formed and a firstsegment body 14 a in which an intake air passage 13 d of the #4 cylinder2 d is formed.

As illustrated in FIGS. 1 and 2, each of the first throttle unit 11 andthe second throttle unit 12 further includes a throttle shaft 15,throttle valves 16 b to 16 d, a motor 17 (motor), decelerationmechanisms 20 and 45, a return spring 21, and a throttle position sensor22. Note that FIG. 2 illustrates the internal structure of the secondthrottle unit 12 and the intake air passage 13 c is provided with thethrottle valve 16 c while the intake air passage 13 d is provided withthe throttle valve 16 d. In the first throttle unit 11, the intake airpassage 13 a is provided with the throttle valve 16 a while the intakeair passage 13 b is provided with the throttle valve 16 b.

The first segment body 14 a and the second segment body 14 b aredisposed to be aligned in the left-right direction (vehicle widthdirection) in accordance with the corresponding cylinders 2 a to 2 d toform a unit body 23 (throttle body).

The intake air passages 13 a to 13 d are formed to extendperpendicularly (in the front-back direction in FIGS. 1 and 2) to theleft-right direction. The throttle shaft 15 extends in the vehicle widthdirection through the unit body 23, passes through the inside of the twointake air passages (13 a and 13 c or 13 c and 13 d), and is rotatablysupported by the unit body 23.

The throttle valves 16 a to 16 d are disk-shaped members that havesubstantially the same diameter as the inner diameter of the intake airpassages 13 a to 13 d, are secured to the throttle shaft 15, and aredisposed inside the intake air passages 13 a to 13 d. The throttlevalves 16 a to 16 d rotate inside the intake air passages 13 a to 13 dalong with rotation of the throttle shaft 15 and can rotate at anarbitrary angle between a closed position at which the intake airpassages 13 a to 13 d are closed and an opened position at which theintake air passages 13 a to 13 d are opened.

The motor 17 is an electric motor. The motor 17 is secured to the secondsegment body 14 b in each of the throttle units 11 and 12 and isdisposed such that a rotation drive shaft 24 is parallel to the throttleshaft 15.

The deceleration mechanisms 20 and 45 are disposed between the firstsegment body 14 a and the second segment body 14 b. As illustrated inFIGS. 3 and 4, the deceleration mechanisms 20 and 45 have anintermediate axis 25, a first gear 26 secured to the rotation driveshaft 24 of the motor 17, a second gear 27 secured to the intermediateaxis 25 and engaged with the first gear 26, a third gear 28 secured tothe intermediate axis 25, and a fourth gear 29 secured to the throttleshaft 15 and engaged with the third gear 28. The intermediate axis 25 isdisposed to be parallel to the rotation drive shaft 24 and the throttleshaft 15 and is rotatably supported by the unit body 23.

The deceleration mechanisms 20 and 45 transmit the rotation of therotation drive shaft 24 of the motor 17 to the first gear 26, the secondgear 27, the intermediate axis 25, the third gear 28, and the fourthgear 29 in this order to decelerate the rotation and drive and rotatethe throttle shaft 15.

The return spring 21 is a torsion spring disposed to be wound around thethrottle shaft 15 several times and including one end portion supportedby the unit body 23 and the other end portion supported by the throttleshaft 15. The return spring 21 biases the throttle shaft 15 to bring thethrottle valves 16 c and 16 d into the closed state.

The throttle position sensor 22 is provided at the one end portion ofthe throttle shaft 15 and functions to detect the rotational angle ofthe throttle shaft 15. The throttle position sensor 22 is disposed inthe first segment body 14 a, for example.

As illustrated in FIG. 1, the second segment bodies 14 b of the firstthrottle unit 11 and the second throttle unit 12 are disposed inward inthe left-right direction, that is, the motor 17 (motor) of the firstthrottle unit 11 and the motor 17 (motor) of the second throttle unit 12are disposed inward in the left-right direction, and the throttleposition sensor 22 is disposed outward in the left-right direction, inthe throttle device 10.

Also, the first throttle unit 11 includes fuel injection valves 30 a and30 b injecting a fuel into the intake air passages 13 a and 13 b. Thesecond throttle unit 12 includes fuel injection valves 30 c and 30 dinjecting a fuel into the intake air passages 13 a and 13 b. In otherwords, the throttle device 10 includes a total of four fuel injectionvalves 30 a to 30 d corresponding to the cylinders 2 a to 2 d.

The fuel is supplied from a fuel pump, which is not illustrated, to thetwo fuel injection valves 30 a and 30 b included in the first throttleunit 11 via a fuel pipe 31. Also, the fuel is supplied from a fuel pump,which is not illustrated, to the two fuel injection valves 30 c and 30 dincluded in the second throttle unit 12 via a fuel pipe 32.

FIG. 5 is an electric circuit diagram for driving the throttle device10.

Driving of each of the motor 17 of the first throttle unit 11 and themotor 17 of the second throttle unit 12 in the throttle device 10 iscontrolled by the control unit 40.

The control unit 40 is a control device for controlling operations ofthe engine 1 and is configured to include an input/output device, astorage device (such as a ROM, a RAM, or a nonvolatile RAM), a centralprocessing unit (CPU), and the like. The control unit 40 inputs a degreeof opening of an accelerator detected by an accelerator opening degreesensor 41 provided in the vehicle, applies a predetermined voltage ofthe motor 17 of the first throttle unit 11 and the motor 17 of thesecond throttle unit 12, outputs a drive current, controls driving ofeach motor 17, and controls operations of each of the fuel injectionvalves 30 a to 30 d. At this time, the rotational angle of the throttleshaft 15 detected by the throttle position sensor 22 is input for eachof the first throttle unit 11 and the second throttle unit 12, andfeedback control is performed such that the rotational angle of thethrottle shaft 15 is obtained in accordance with the degree ofaccelerator opening.

In addition, the control unit 40 includes a cylinder deactivationcontrol unit 42 executing a cylinder deactivated operation.

The cylinder deactivation control unit 42 controls driving of the motor17 such that the throttle valves 16 c and 16 d of the second throttleunit 12 are in a fully opened state (predetermined degree of opening)and stops injection of the fuel performed by the fuel injection valves30 c and 30 d in a predetermined operating region of the engine 1, forexample, at the time of a request for a low output to obtain a degree ofaccelerator opening of equal to or less than a predetermined value. Notethat the operations of the motor 17 of the first throttle unit 11 andthe fuel injection valves 30 a and 30 b are controlled in accordancewith a requested output based on an accelerator operation or the likeeven in the predetermined operating region.

In this manner, the combustion in the two #3 and #4 cylinders 2 c and 2d from among the four #1 to #4 cylinders 2 a to 2 d in the engine 1 isstopped and the output stops. Thus, since fuel consumption at the #3 and#4 cylinders 2 c and 2 d becomes zero, and the throttle valves 16 c and16 d are brought into the fully opened state in the #3 and #4 cylinders2 c and 2 d, it is possible to reduce a pumping loss and to curb fuelconsumption in the entire engine 1.

In this embodiment, a deceleration ratio of the deceleration mechanism20 in the first throttle unit 11 and a deceleration ratio of thedeceleration mechanism 45 in the second throttle unit 12 are set to bedifferent from each other.

As illustrated in FIGS. 3 and 4, a gear ratio of the third gear 28 andthe fourth gear 29 of the deceleration mechanism 45 in the secondthrottle unit 12 is set to be lower than a gear ratio of the third gear28 and the fourth gear 29 of the deceleration mechanism 20 in the firstthrottle unit 11. Note that the gear ratios of the first gear 26 and thesecond gear 27 may be set to be different from each other, or both thegear ratios of the first gear 26 and the second gear 27 and the gear thegear ratios of the third gear 28 and the fourth gear 29 may be set to bedifferent from each other.

In this manner, it is possible to set the rotation speed of the throttleshaft 15 in the second throttle unit 12 used for the cylinders 2 c and 2d that are subjected to cylinder deactivation in the cylinderdeactivated operation to be higher than the rotation speed of thethrottle shaft 15 in the first throttle unit 11 used for the cylinders 2a and 2 b that are not subjected to cylinder deactivation even when therotation speeds of rotation drive axes 24 of the motors 17 are the samein the first throttle unit 11 and the second throttle unit 12.

FIG. 6 is a graph illustrating a transition example of a degree ofthrottle opening at the time of transition from the cylinder deactivatedoperation to the ordinary operation. FIG. 6 illustrates transition ofthe degrees of opening of the throttle valves 16 a, 16 b, 16 c, and 16 duntil the degrees of opening of the throttle valves 16 a, 16 b, 16 c,and 16 d transition to a predetermined degree of opening Vo1 when thecylinder deactivated operation is released from the cylinder deactivatedoperation state and transition to the ordinary operation is achieved.Note that FIG. 6 illustrates a case in which a requested output of theengine slightly increases from the cylinder deactivated operation stateand transitions to the ordinary operation in which combustion is carriedout in all the cylinders 2 a to 2 d is achieved. Note that in order toavoid large variation in the output of the entire engine 1, when therequested output of the engine 1 slightly increases from the cylinderdeactivated operation state and switching to the ordinary operation isachieved, the degree of opening (predetermined degree of opening Vo2) ofthe throttle valves 16 a and 16 b in the cylinder deactivated operationstate is greater than the degree of opening (predetermined degree ofopening Vo1) of the throttle valves 16 a, 16 b, 16 c, and 16 d in theordinary operation.

As illustrated in FIG. 6, the degree of opening of the throttle valves16 a and 16 b in the first throttle unit 11 is the degree of throttleopening Vo2 corresponding to the requested output based on anaccelerator operation or the like while the degree of opening of thethrottle valves 16 b and 16 d in the second throttle unit 12 is a fullyopened state. Also, in a case in which an operation of opening theaccelerator is performed, a requested output increases, and the cylinderdeactivated operation is released, for example, motors 17 are controlledrespectively to achieve the ordinary operation in which all the throttlevalves 16 a to 16 d have the requested degree of opening Vo1 based onthe accelerator operation or the like.

Here, in a case in which the deceleration ratio of the decelerationmechanism 45 in the second throttle unit 12 is the same as thedeceleration ratio of the deceleration mechanism 20 in the firstthrottle unit 11 in a comparative example, the degree of opening of thethrottle valves 16 c and 16 d in the second throttle unit 12 and thedegree of opening (represented by the thin solid line in FIG. 6) of thethrottle valves 16 a and 16 b in the first throttle unit 11 transitionat an equivalent speed as represented by the dashed line in FIG. 6.Thus, a period of time during which the degree of opening of thethrottle valves 16 c and 16 d does not reach the predetermined degree ofopening Vo1 occurs even when the degree of opening of the throttlevalves 16 a and 16 b reaches the predetermined degree of opening Vo1.Thus, there is a possibility that the degrees of opening of the throttlevalves 16 a and 16 b and of the throttle valves 16 c and 16 d do notconform to each other over the entire period of time of the switchingfrom the cylinder deactivated operation to the ordinary operation andimmediately after the transition from the cylinder deactivated operationto the ordinary operation and the driver has an uncomfortable feelingfrom the output of the engine 1 due to a difference in output of the #1and #2 cylinders 2 a and 2 b and the #3 and #4 cylinders 2 c and 2 d.

On the other hand, since the deceleration ratio of the decelerationmechanism 45 in the second throttle unit 12 is smaller than thedeceleration ratio of the deceleration mechanism 20 in the firstthrottle unit 11 in this embodiment, the degree of opening of thethrottle valves 16 c and 16 d conforms to the degree of opening of thethrottle valves 16 a and 16 b before the degree of opening of thethrottle valves 16 a and 16 b in the first throttle unit 11 reaches thepredetermined degree of opening Vo1 as represented by the thick solidline in FIG. 6. Note that each motor 17 may be controlled such that thetransition is carried out with the degree of opening of the throttlevalves 16 c and 16 d and the degree of opening of the throttle valves 16a and 16 b maintained to conform to each other, until the predetermineddegree of opening Vo1 is reached after the degree of opening of thethrottle valves 16 c and 16 d and the degree of opening of the throttlevalves 16 a and 16 b conform to each other.

Since the degree of opening of the throttle valves 16 a and 16 b in thefirst throttle unit 11 thus conforms to the degree of opening of thethrottle valves 16 c and 16 d in the second throttle unit 12 in an earlystage when the transition from the cylinder deactivated operation to theordinary operation is achieved in this embodiment, it is possible toquickly cause the outputs of the #1 and #2 cylinders 2 a and 2 b toconform to the outputs of the #3 and #4 cylinders 2 c and 2 d, to smooththe output of the engine, and thereby to improve an output feeling ofthe engine 1.

As described above, the throttle device 10 according to the presentembodiment is the multi-throttle device 10 provided with the throttlevalves 16 a to 16 d in the intake air passages 13 a to 13 d of the fourcylinders 2 a to 2 d in the engine 1 and includes the two throttle units11 and 12. The throttle device 10 has a structure in which the motor 17included in the first throttle unit 11 drives the two throttle valves 16a and 16 b while the motor 17 included in the second throttle unit 12drives the two throttle valves 16 a and 16 b.

Also, the deceleration mechanism 20 of the first throttle unit 11 andthe deceleration mechanism 45 of the second throttle unit 12 are set tohave different deceleration ratio from each other in the presentembodiment.

In this manner, it is possible to cause the throttle valves 16 a and 16b in the first throttle unit 11 and the throttle valves 16 c and 16 d inthe second throttle unit 12 to have different responsiveness to valveopening degree control with a simple configuration by setting thedeceleration mechanism 20 and the deceleration mechanism 45 to havedifferent deceleration ratio from each other.

Further, the engine 1 according to the present embodiment include thecylinder deactivated operation function and changes the degree ofopening of the throttle valve 16 b in the second throttle unit 12corresponding to a part of the four cylinders 2 a to 2 d, namely thecylinders 2 c and 2 d into a fully opened state at the time of a lowrequested output.

Since the deceleration ratio of the deceleration mechanism 45 in thesecond throttle unit 12 that are operated in the fully opened state inthe cylinder deactivated operation function is set to be smaller thanthe deceleration ratio of the deceleration mechanism 20 in the firstthrottle unit 11 in which the cylinder deactivation is not performed inthe cylinder deactivated operation to obtain a specification that thereturn spring 21 in the second throttle unit 12 has in the presentembodiment, it is possible to curb an uncomfortable feeling of theoutput of the engine 1 with a simple configuration by quickly loweringthe degree of opening of the throttle valves 16 c and 16 d in the secondthrottle unit 12 to the same degree of opening as that of the throttlevalves 16 a and 16 b in the first throttle unit 11 when the cylinderdeactivated operation is released.

Also, the deceleration mechanisms 20 and 45 according to theaforementioned embodiment may have a structure in which the set torqueof the return spring 21 can be changed. The set torque of the returnspring 21 is a biasing torque caused by the return spring 21 toward aclosed direction in a closed state of the throttle valves 16 a to 16 d.

FIG. 7 is an assembly diagram of an attachment portion of the returnspring 21 in the second throttle unit 12. FIG. 8 is an explanatorydiagram illustrating an installation state of the return spring 21 inthe first throttle unit 11. FIG. 9 is an explanatory diagramillustrating an installation state of the return spring 21 in the secondthrottle unit 12. Note that the up-down direction in FIG. 7 is oppositeof that in FIGS. 1 to 4, 8, and 9 for easiness in viewing the attachmentportion of the return spring 21, and the throttle shaft 15 isillustrated above the motor 17. Although the first throttle unit 11 andthe second throttle unit 12 are laterally symmetric, on the left andright sides, the first throttle unit 11 and the second throttle unit 12are illustrated in a left-side-right manner in FIG. 8 for easycomparison therebetween.

As illustrated in FIG. 7, a cylindrical rib 52 projecting outward in theaxial line direction of an insertion hole 51, into which the throttleshaft 15 is inserted, is formed around the insertion hole 51 at an endportion of the unit body 23 (specifically, an end portion of the secondsegment body 14 b on the side of the deceleration mechanism 45). Also,two projections (a first projection 53 a and a second projection 53 b)are formed outward in the radial direction of the rib 52 at the endportion of the second segment body 14 b. The first projection 53 a andthe second projection 53 b have columnar shapes with a diameter of aboutseveral mm, for example, project outward in the axial line direction ofthe insertion hole 51 in parallel with the rib 52, and project up to thevicinity of the distal end of the rib 52. The first projection 53 a andthe second projection 53 b are disposed at mutually opposite positionswith the insertion hole 51 sandwiched therebetween, for example, at aninterval from each other in the circumferential direction on aconcentric circle around the insertion hole 51 at the center.

Both end portions 21 a and 21 b of the return spring 21 project outwardin the radial direction. The return spring 21 is configured to bedisposed with the distal end portion of the rib 52 inserted thereintosuch that the end portion 21 a on the second segment body 14 b can belocked at the first projection 53 a and the second projection 53 b.

The fourth gear 29 and the throttle shaft 15 are secured to each othervia a disk-shaped hook plate 55. A shaft coupling hole 55 a into whichthe throttle shaft 15 is inserted is provided at the center of the hookplate 55. The distal end portions of the shaft coupling hole 55 a andthe throttle shaft 15 are formed into rectangular shapes, for example,and the throttle shaft 15 and the hook plate 55 are coupled so as not tobe able to rotate relative to each other, that is, such that therotation of the fourth gear 29 is transmitted to the throttle shaft 15.

A step difference 15 a positioning the hook plate 55 in the axialdirection is provided at the distal end portion of the throttle shaft15. The return spring 21 is disposed between the hook plate 55 disposedwith the distal end portion of the throttle shaft 15 inserted thereintoand the second segment body 14 b. The fourth gear 29 is secured to theoutside of the hook plate 55 with a plurality of bolts, for example.

A first hook 55 b, a second hook 55 d, and a stopper 55 c extendingoutward in the radial direction with distal ends bent toward the axialdirection (on the side of the second segment body 14 b) are formed atouter peripheral end portions of the hook plate 55. The first hook 55 band the second hook 55 d are disposed at an interval from each other inthe circumferential direction on a concentric circle around the shaftcoupling hole 55 a at the center. Also, grooves, for example, are formedin both the first hook 55 b and the second hook 55 d for easily lockingthe end portion 21 b of the return spring 21.

The stopper 56 c abuts on a stopper bolt 56 provided in the secondsegment body 14 b to prevent rotation of the throttle shaft 15 in onedirection (right rotation in FIG. 7). The stopper bolt 56 can adjust theposition at which the stopper bolt 56 abuts on the stopper 55 c.

The return spring 21 biases the hook plate 55 in the one rotationdirection (right rotation in FIG. 7) relative to the second segment body14 b, and the rotation thereof is prevented at a predetermined rotationposition by the stopper 55 c. In other words, the throttle shaft 15 isbiased to rotate relative to the unit body 23 by a biasing force of thereturn spring 21. In this manner, the throttle valves 16 c and 16 d (16a and 16 b in the first throttle unit 11) are closed when the motor 17does not operate.

Also, the fourth gear 29 rotates against the biasing of the returnspring 21 (left rotation in FIG. 7) via the deceleration mechanism 45 byoperating the motor 17.

In the deceleration mechanisms 20 and 45 according to this embodiment,the projections 53 a and 53 b are provided at two locations of thesecond segment body 14 b, and the end portion 21 a of the return spring21 on the side of the second segment body 14 b can be selectively lockedat any of these projections 53 a and 53 b. The throttle valves 16 c and16 d (16 a and 16 b) are biased in the closed direction by biasing ofthe return spring 21, and the throttle valves 16 c and 16 d (16 a and 16b) are brought into a closed state when the motor 17 does not operate.The biasing torque of the return spring 21 in the closed state, that is,the set torque maintaining the throttle valves 16 c and 16 d (16 a and16 b) in the closed state is defined by the locking position of the endportion 21 a of the return spring 21.

As illustrated in FIG. 8, the set torque is set to be relatively smallby locking the end portion 21 a of the return spring 21 at the firstprojection 53 a in the first throttle unit 11.

As illustrated in FIG. 9, the set torque is set to be relatively largeby locking the end portion 21 a of the return spring 21 at the secondprojection 53 b in the second throttle unit 12.

Also, the first hook 55 b and the second hook 55 d are formed in thehook plate 55, and the set torque can also be changed depending of whichof the first hook 55 b and the second hook 55 d the end portion 21 b ofthe return spring 21 is locked at.

The set torque is set to be relatively small by locking the end portion21 b of the return spring 21 at the first hook 55 b in the firstthrottle unit 11.

The set torque is set to be relatively large by locking the end portion21 b of the return spring 21 at the second hook 55 d in the secondthrottle unit 12.

It is thus possible to cause the throttle valves 16 c and 16 d in thesecond throttle unit 12 that is subjected to cylinder deactivation tofurther quickly perform the closing operation as compared with thethrottle valves 16 a and 16 b in the first throttle unit 11 that is notsubjected to cylinder deactivation when the throttle valves 16 a to 16 din the first throttle unit 11 and the second throttle unit 12 areoperated from the fully opened state to the fully closed state.

Although the description of the embodiments will now end, the aspects ofthe present invention are not limited to the aforementioned embodiments.For example, although the present invention is applied to the engine 1provided with the cylinder deactivated function in the aforementionedembodiments, the present invention may be applied to an engine with nocylinder deactivated function.

It is possible to immediately solve differences in degrees of opening ofa plurality of throttle valves in a case in which control is performedto obtain the same degree of opening from the state in which the degreesof opening differ from each other, in an engine in which a state wherethe degrees of opening of the plurality of throttle valves differ fromeach other may occur regardless of the engine being not provided withthe cylinder deactivated operation function. It is thus possible toachieve smooth operations of the engine with a simple configuration.

Although the present invention is applied to the throttle device 10 inthe four-cylinder engine 1 in the embodiments, the present invention maybe applied to a throttle device for an engine with a plurality ofcylinders instead of the four-cylinder engine.

Although the throttle device 10 according to the embodiment has the twothrottle units 11 and 12, and the total of two motors 17 for each two ofthe four cylinders drive the throttle valves for the cylinders, thethrottle device may include three or more motors. The number of throttlevalves operated by each motor may be any number instead of two.

The throttle device according to the present invention can be employedfor an engine used for applications other than the motorcycle.

The present invention is employed in a multi-cylinder engine and canwidely be applied to a throttle device in which a plurality of motorsshare operations of opening and closing a plurality of throttle valves.

What is claimed is:
 1. A throttle device comprising: a plurality ofthrottle units provided in an engine for each of cylinders or for eachof cylinder groups, each of the throttle units including a throttle bodyhaving intake air passages corresponding to the plurality of cylindersof the engine, a throttle shaft rotatably supported by the throttlebody, throttle valves secured to the throttle shaft to open and closethe intake air passages for the cylinders, a motor, and a deceleratordecelerating rotation of a drive shaft of the motor and transmitting thedecelerated rotation to the throttle shaft, wherein a cylinderdeactivation control unit stopping operations of the motor of a secondthrottle unit out of the plurality of throttle units to cause thethrottle valves of the second throttle unit to have a predetermineddegree of opening in a predetermined operation region of the engine anddeactivating combustion of the cylinders or the cylinder groupscorresponding to the second throttle unit, and a deceleration ratio ofthe decelerator in the second throttle unit is lower than thedeceleration ratio of the decelerator in a first throttle unit out ofthe plurality of throttle units.
 2. The throttle device according toclaim 1, wherein the predetermined degree of opening is fully openedstate.
 3. The throttle device according to claim 1, wherein two unitsbeing the throttle units are provided in the engine.
 4. The throttledevice according to claim 2, wherein two units being the throttle unitsare provided in the engine.
 5. The throttle device according to claim 1,wherein the throttle device is provided in the engine of a motorcycle.6. The throttle device according to claim 2, wherein the throttle deviceis provided in the engine of a motorcycle.
 7. The throttle deviceaccording to claim 3, wherein the throttle device is provided in theengine of a motorcycle.
 8. The throttle device according to claim 4,wherein the throttle device is provided in the engine of a motorcycle.